Japanese knotweed invaded many countries, and it cost 6.3 billion yuan to wipe out

The discovery of knotweed

Plant invasions are not uncommon today, and with proper biocontrol and pesticide treatments, plant invasions can be more effective than animal invasions.

Because plants are not as active as animals or insects, and their transmission media is limited, the growth mode and growth time need certain conditions.

But there are still a lot of troublesome plant invasions, and if the roots are not completely destroyed, the plant may reappear the next year.

Japanese knotweed is just such a plant. The name implies that it is definitely not a simple plant.

True to its name, the origin of Japanese knotweed is already in its name, and so is its performance.

Knotweed is a big headache all over the world, not just in Japan.

The Japanese have long recorded the history of the consumption and use of knotweed, which can be found everywhere in the wild in Japan.

The folk names of knotweed vary according to different regions, such as Mie Prefecture, Nagano, Nara, Akita, and Yamagata.

There is no scientific statistical data for it because of the shortage of food in different places.

Knotweed will grow with young leaves and buds that look like asparagus, but the taste will be very sour. To eat this wild vegetable, the skin must be removed, then boiled in water for half a day, and then boiled in boiling water.

The Japanese people have many methods to deal with it. For example, people in Kochi Prefecture will wipe the cleaned shoots with kosher salt mixture.

In places like central Kagawa Prefecture, the peeled shoots are pickled in a 10 percent magnesium chloride mixture.

It can be seen that in order to deal with this wild vegetable well, it must be in a high concentration of salt and alkali environment to effectively eliminate their biohazard.

That's not so easy in the UK, where people don't know how to cook and knotweed is not a plant you'd think of eating.

And, of course, its intense acidity and intractable roots.

The amazing plant was discovered by the Dutch naturalist Marten Hutuin in the 18th century, when he named it "Reynoutria japonica".

But the original records of the plant were lost, so for a long time, it wasn't entirely clear who or what it was.

The stems and leaves of this polygonum

The name given by Marten is now the binomial name for Japanese knotweed.

About 150 years after Marten's discovery, Bavarian botanist Philipp von Siebold rediscovered the plant.

Siebold and his assistants eventually named the plant Knotweed.

It wasn't until the late 19th and early 20th centuries that the Japanese botanist Makino suddenly understood that the plants Hutuin and Siebold had discovered were the same species.

The Tigers invaded

As one of the most affected and harmful "weeds" in the UK today, knotweed has been propagated and spread throughout the UK through contaminated soil and root debris.

Since 1850, Japanese knotweed has spread throughout Britain.

Bristol, Nottingham, Rotherham and Glasgow were the worst hit areas.

Siebold probably had no idea when he brought Japan back to England that the plant would have such an impact at home that it would affect the entire British flora.

During his stay in Japan, Siebold collected many plants, more than 1,000 species, and planted them on islands near Nagasaki for observation and record.

Siebold would then periodically pack the plants and send them to the British Botanic Garden, where Japanese knotweed was packaged in an unmarked box in 1850.

It was this omission that led to the downfall of later British plants, when they arrived in England, Japanese knotweed grew rapidly.

Even gardeners say it is easy to grow and the little white flowers that bloom are charming.

Many tourists also like this plant.

At the time, knotweed was supplied mainly to British plantations and wealthy classes, mainly because its flowers and oddly shaped leaves were considered so fashionable.

In spring, fleshy reddish-purple buds emerge from deep red buds on the ground.

Succulent buds grow rapidly and produce dense, tall bamboo-like vines in summer, with milky spikes of flowers up to 15 cm in late summer and early autumn.

And that's one of the things about knotweed, these cane-like roots have purple spots and branches along their length from the nodes.

They have heart-shaped or spatular-shaped leaves that can grow up to 14 cm long and alternate along the stem.

In winter, the stems die and fall to the ground. But the dried stems will remain for several months or longer.

The Japanese knotweed is rare in the whole plant kingdom for its strong growth and almost woody stems, which can grow up to 20 centimeters per day.

Knotweed certainly brought life to the grey skies of 19th century industrialised and built-up Britain.

From railway lines to riverbanks to gardeners' plantations, Japanese knotweed was very popular.

Despite the rapid growth of Japanese knotweed, the British are confident that they can manage the plant, especially as it came to the country mainly as an import.

But at the time, no one could have imagined that Japanese knotweed could be propagated asexually in large numbers.

In winter, the stems of Japanese knotweed turn completely brown and at first glance appear dead.

But in fact, the knotweed roots are buried in the ground, forming a vast network of roots and stems, while the knotweed still draws on the nutrients from the ground and thrives.

Measures should be taken according to local conditions

Because of this, Japanese knotweed has become one of the most powerful invasive species in the world.

Strong, invasive roots can damage concrete foundations, including many roads, and reduce the ability of flood control channels to carry water.

Spreading knotweed can shade other plants and grow more vigorously in intricate structures, increasing fire risk.

Drought resistance, roots deep into the ground, and itself extremely resistant to cutting function. If not completely destroyed from the roots, knotweed will sprout again in the next growth cycle.

It costs the UK £6.3bn a year to remove the effects of Japanese knotweed - up to £1,000 for every 0.8 square metre of weeding - and it is now illegal to grow it in the wild.

Worst of all, because knotweed can destroy even though neonicotinoid herbicides are effective at stopping the growth of Japanese knotweed.

But even so, Japanese knotweed will take years of weeding to eradicate, and neonicotinoid herbicides are tightly regulated in the UK.

But at home, Japanese knotweed is grown in large numbers.

Although knotweed is a serious plant in foreign countries, it is regarded as a treasure in China.

Besides being edible, the most important thing about knotweed is its medicinal value.

The rhizome of knotweed is a major source of resveratrol in dietary supplements.

This substance has extremely high antioxidant properties and in combination with oligomeric proanthocyanidins may support the treatment of liver disease or improve skin conditions after oxidative stress.